CHAPTER 19 INTERRUPT FUNCTIONS
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CHAPTER 19 INTERRUPT FUNCTIONS
The interrupt function switches the program execution to other processing. When the branch processing is finished, the
program returns to the interrupted processing.
The number of interrupt sources differs, depending on the product.
19.1
Interrupt Function Types
The following two types of interrupt functions are used.
(1) Maskable interrupts
These interrupts undergo mask control. Maskable interrupts can be divided into four priority groups by setting
the priority specification flag registers (PR00L, PR00H, PR01L, PR01H, PR02L, PR02H, PR10L, PR10H,
PR11L, PR11H, PR12L, PR12H).
Multiple interrupt servicing can be applied to low-priority interrupts when high-priority interrupts are generated. If
two or more interrupt requests, each having the same priority, are simultaneously generated, then they are
processed according to the default priority of vectored interrupt servicing. Default priority, see
and
.
A standby release signal is generated and STOP, HALT, and SNOOZE modes are released.
External interrupt requests and internal interrupt requests are provided as maskable interrupts.
(2) Software interrupt
This is a vectored interrupt generated by executing the BRK instruction. It is acknowledged even when
interrupts are disabled. The software interrupt does not undergo interrupt priority control.
19.2
Interrupt Sources and Configuration
Interrupt sources include maskable interrupts and software interrupts. In addition, they also have up to seven reset
sources (see
). The vector codes that store the program start address when branching due
to the generation of a reset or various interrupt requests are two bytes each, so interrupts jump to a 64 K address of
00000H to 0FFFFH.
Summary of Contents for RL78/G1H
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